Bat-box schemes are often set up as mitigation for the loss of potential bat roosts, or for general conservation or education purposes. It is important that they are carefully planned: poorly sited or incorrectly chosen bat-boxes are unlikely to be successful. The design of bat-boxes is continually developing, as our knowledge of bat ecology expands. At present there are three commonly used styles of bat box.

	Traditional wooden bat-boxes can be quite successful and have the benefit of being economical. As their heat insulation properties are limited it is normal to site two boxes together on one tree, facing south-east and south-west. This allows bats to move between them for optimum temperature, as the sun moves. They have a limited life, as the wood cannot be treated.
	Schwegler 2F bat-boxes are made from woodcrete, a sawdust and cement mixture which combines a good surface for the bats to grip and good thermal insulation. They are usually sited singly, facing south and appear to be significantly better-used than traditional boxes. They have the disadvantage of being vulnerable to vandalism as the material is quite brittle. Also available with an internal wooden baffle, to deter nesting birds.
	Schwegler 1FF bat-boxes are made of a similar material to the 2F above and have the benefit of being less prone to vandalism, due to their low profile. They are especially attractive to Pipistrelle species, which are attracted to the narrow crevice within. However, if it is intended that boxes be checked for occupancy by licensed bat-workers, these can be particularly awkward to open without disturbing the bats within.

Positioning. Boxes should be at least 4m above the ground, facing roughly south. There should be no overhanging branches to obstruct free access, but exposed positions should be avoided. Consideration should be given to commuting corridors leading to potential foraging sites, especially for woodland species. Using headless nails prevents  boxes from being dislodged by tree growth.

Checking Boxes. An annual check of boxes in the autumn is advantageous, as it allows their use to be evaluated and any obstructions such as bird and wasp nests or excessive droppings to be cleared. Once bats start to use a box it has the same legal protection as any other bat roost so checks may only be carried out by a licensed bat-worker.

© David Dodds Ecology 2007